Method and apparatus for recording and reproducing sound waves



May 20, 1930.

B. KWARTIN METHOD AND APPARATUS FOR RECORDING AND REPRODUCING SOUND WAVES Filed June 16, 1928 I I I I unnnnnnnnunnuunennunasan=====-=-n===-===a=-=---a menial BERNARD KwAR'rm Patented May 2t), 1930 i I UNITED STATES PATENT OFFICE BERNARD KWARTIN, F PHILADELPHIA, PENNSYLVANIA" METHOD AND APPARATUS FOR RECORDING AND REPRODUCING SOUND WAVES I Application filed June 16, 1928. Serial No. 285,850.

This invention relates generally to imducing upon the sound record film an auxprovements in the art ot'recording and reiliary record which I have termed the dyproducing sounds and more particularly to namic record, the purpose of which is to an apparatus for and method of improving impart automatically to the reproduced 5 the character of reproduction of sounds sounds the necessary variations and contrasts 5 which have been photog; aphically recorded of loudness or power. Although this variaupon a photographic film. tion and contrast in power is originally put In the production of talking pictures, into the music during the recording process, this being the commonly accepted term used much of it, if not all, is lost in the usual where picture and sound records are recorded sound record with the result that when the 0 simultaneously upon a photographic film or music is reproduced from the record the vathe like, many serious difiiculties have been rious passages thereof are minus all expresencountered in the various attempts to faithsive emphasis and dynamic shading. It is fully record and reproduce the sound impresto supply the reproduced music with thechau sions, one of the chief difliculties being that it acter and expression which has been lost in 65 has not been possible heretofore to reproduce the sound record that the dynamic record the photographically recorded sounds in such is employed. manner that the reproduction was in accord A still further object of the invention is with the sounds as originally produced so the provision ofaphotographically produced tar as the expressive emphasis and dynamic sound record, irrespective of and apart from 79 shading ot' the latter were concerned. This its applicability for talking pictures, includdifiiculty has been present, of course, irreing as an auxiliary part thereof a dynamic spective of whether or not the photographic or sound shading record. sound record was produced simultaneously A still further object of the invention is with the picture and accordingly it will be the provision of an apparatus for and understood that the present invention is parmethod of utilizing this dynamic record ticularly concerned with the photographifor affording the various passages in the recally produced sound record as distinguished produced selection with that expressive emfrom the picture record. It is well known phasis and dynamic shading following closely 30 that the character of any musical, vocal or the particular emphasis and shading which similar rendition depends largely upon propthe composition originally called for. In er accentuation of the various passages, certhis connection it will be understood, of tain of which must be played or sung in course, that the dynamic record and the crescendo and others in diminuendo or decresound record are operated in synchronism,

35 scendo. suitable means being employed for effecting That department of musical science which the necessary inter-relation between the recrelates to, or treats of, the variation and concords for the purposes specified. trast of loudness or power in tones and in the While in the recording process the sound expressive emphasis and dynamic shading of shading record is obtained by manual con- 40 the various passages is known as the dytrol of a suitable shutter operated in accordnamics of music and it is one of the primary ance with and by one familiar with the score objects of this invention to take into conof the composition, in the reproducing procsideration this field of dynamics in the reess this same record is employed to automaticording and reproduction of photographically impress upon any particular tone or cally recorded sounds such that the musical passage that emphasis and shading which or vocal selections when reproduced will be the score originally called for.

properly accentuated. A still further object of the invention is In furtherance of this primary object the the provision of an arrangement for reproprcsent invention contemplates the provision ducing the beat of a drum the sounds from of an apparatus for photographically prowhich were originally recorded upon a phoemployed to establish electrical variations corresponding to the original sound variations as produced by the recording drum for mechanically operating a separate drum during the reproducing process. This arrangement differs from the usual in that in the present reproduction of the drum record a regular drum is employed for operation in the natural manner (that is, it'is arranged to be struck by'a drum stick) while in the usual photographic sound record reproduction the electrical variations are converted into sound variations by loud-speakers or other such sound reproducing apparatus. Experience has shown that these loud-speakers have been incapable of faithfully reproducing drum sounds with the result that those passages in a musical composition in which a drum is called for have been lacking in character in the reproduction. The present arrangement obviates this difficulty by employing a regular drum arranged to be struck in the natural manner by a drum stick, the photographic film record of the original drum sounds being utilized for efiecting the mechanical operation of the drum stick.

Other objects and objects relating to details of construction and operation will appear more fully hereinafter.

The invention consists substantially in the combination, location, construction and relative arrangement of parts, as well as in the method of usin the same, as will appear more fully hereinafter, as shown in the accompanying drawings, and as finally pointed out in the appended claims. In the accompanying drawings, it being understood that said drawings are merely illustrative of the invention and that the latter may be varied without departing from the spirit or principles thereof:

Figure 1 is a more or less diagrammatic view showing a form of recording apparatus for producing the sound record and the corresponding sound shading reeord'in-accordance with the principles of this invention;

Figure 2 is a fragmentary view of a record produlced by the apparatus shown in Figure 1; an

Figure 3 is a diagrammatic view illustrating an arrangement for reproducing the sound record shown in Figure 2 in accordance with the principles of this invention.

Referring to the drawings and more particularly to Figure 1 which shows an apparatus for photographically recording motion pictures and sound effects upon a film, it will e seen that this apparatus comprises a main casing or box 10 having the rollers 11 and 12 over which the film 13 is arranged to travel. A suitable lens (not shown) may be arranged at the front end of the box for taking the desired pictures, while mounted upon the rear wall 14 of the box are a plurality of recording lamps 15 for throwing light rays of varying intensities upon the film, these recording lamps being energized by electrical variations produced through the use of microphones in the manner well known in the art. Extending transversely across the box and positioned between the recording lamps 15 and the film 11 is a quartz or similar opaque plate 16 provided therein with a plurality of small slits or openings 17 corresponding in number to the recording lamps 15. In the particular instance, two lamps 15 and a corresponding number of openings 17 are employed, each lamp being positioned directly behind its respective opening such that the fluctuating light rays emanating from the lamps will produce individual records upon the film of the sounds influencing the respective lamps. Preferably, the openings 17 are arranged to either side of the space normally occupied by the picture so that the individual sound records will be producedwith the light picture therebetween, but it will be understood that the particular arrangement .of sound and picture records upon the film is immaterial and may be varied as desired. By

properly proportioning the openings 16 the width and length of the beams of light that are directed on the film by the several recording lamps may be rigidly held to the proper limits.

It will further be seen that the provision of a number of recording lamps arranged to be individually energized makes it possible to produce upon a common film a corresponding number of sound records, each of which records is produced by the action of different sound waves upon a number of microphones 18. In this connection it may be that the subject positioned in front of the recording apparatus isra group of artists playing a number of instruments in ensemble, among them one or more drums. Were all of the sounds produced by these instruments to be collected for subsequent translation into electrical variations through the use of a single microphone, the record as produced upon the film would not be true and faithful to the sounds as originally produced by the various instruments, this for the reason that the single microphone is not well adapted to take with equal efiiciency a number of different sounds of different tonal values. Conversely, the same holds true in the simultaneous reords, one of these records being of the sounds produced by a drum. In the production of this drum record a microphone is used which is best suited for the purpose, while in the reproduction thereof, instead of. using a loud speaker, a drum 19 is employed (see Figure For reproducing the music produced by instruments other than a drum, a loud speaker 20 may be employed, it being understood, of course, that as many loud speakers are employed as there are individual sound records (exclusive of the drum record) upon the film.

Figure 2 shows one form of record as produced by the arrangementhereinbefore described, this record comprising a single-strip of photographic film upon which have been simultaneously recorded the motion pictures 21 and the sound records 22 and 23, the record 22 being of the drum while the record 23 may be 'of another instrument or group of instruments. If desired, a number of records similar to 23 may be had upon the same film depending entirely upon the number of microphones and recording lamps employed.

Referring to Figure 1, it will be seen that the multiple sound record hereinbefore described is reproduced by means of photo-electric cells 24 which are influenced by the several sound records 22 and 23 passing their re spective light sources 25. A separate cell is employed for each record, each cell being operative to convert the light variations into electrical variations. It will be observed that the photo-electric cell 24 corresponding to the drum record 22 is connected to a solenoid 26 through an amplifying circuit 27, while the other cell'24c corresponding to the record 23 is connected to the loud speaker 20 through a separate amplifying circuit 28. As the sound wave impressions of the drum record 22 influence its respective photo-electric cell the solenoid 26 is correspondingly energized with the result that the striker arm or drum stick 29 is caused to beat the drum 19. At the same time, the other sound record 23 influences its respective photo-electric cell, with the result that the loud speaker 20 is operated to reproduce the sounds of the record 23. It will be observed that each of the circuits 27 and 28 include a suitable amount of resistance 30 for limiting the amplified current to a predetermined value.

That portion of the invention which is concerned with the dynamics of sound reproduction will now be considered. As has already been stated, one of the main difliculties centuation of the various passages, certain of which should be played or sung in crescendo and others in diminuendo, it is essential to give careful consideration to that department of musical science which relates to, or

treats of, the variation and contrast of loudness or power in tones. In furtherance of this, the present invention contemplates the provision of apparatus for photographically producing upon the sound record film an auxiliary sound shading record, described hereinafter and defined in the claims as the dynamic record, the purpose of which is to supply the reproduced music with its intended character and expression. Although this variation and contrast in power is origi nally put into the music during the recordmg process, much of it, if not all, is lost in the sound record with the result that when the music is reproduced therefrom the various passages are minus all expressive emphasis and dynamic shading. 1

Referring again to Figure 1, it will be ob served that the transversely extending opaque plate 16 is provided to one side thereof with a relatively wide opening 31 (that is, as compared with the opening 17), the vertical dimension of which is the same as that of the openings 17. Mounted in the rear wall of the casing 10 and in registry with the opening 31 is a lamp 32 energized from a constantsource of supply 33. A shutter 34 which is preferably arranged to slide through the side wall of the casing 10 operates to cover the opening 31 to greater or lesser extent, the exteriorly projecting portion of the shutter being provided with a suitable handle or knob 35 for manual operation thereof. The amount of light rays emanating from the lamp 32 which are directed through the opening 31 and upon the film 13 is governed entirely by the extent to which the shutter 34 covers said opening, it being observed that when the shutter is moved all the way in the opening 31 will be entirely covered and no portion of the film will be exposed to the lamp 32. On the other hand, when the shutter 34 is pulled all the way out the opening 31 will be entirely uncovered with the result that a portion of the film 13 corresponding in transverse width to that of opening 31 will be exposed to the lamp 32. Intermediate positions of the shutter will result in more or less of the film being exposed to the lamp 32, but in no case will any other portion of the film be exposed to this lamp than that which passes by the opening 31.

As the film 13 passes through the casing 10, the several transverse regions thereof are exposed to the lamps 17 and 32 to produce the sound records 22 and 23 and the dynamic or sound shading record 35 (see Figure 2). This dynamic record is produced upon the film 13 simultaneously with the sound records by means of the shutter 34, said who is familiar with the score of the particular composition being recorded.

Inasmuch as the records are originally formed upon a master film from which the actual sound reproducing films are in turn produced, it will be understood that in the master film the dark areas or markings in both the sound records and in the dynamic recordiare produced by the more intense light and correspond to the louder sounds while the lighter areas or markings, which are produced by less intense light, correspondto the weaker sounds. Conversely, in the reproducing films the darker areas or markings produce the weaker sounds while the lighter areas or markings produce the stronger or louder sounds. Accordingly, when it is desired to give particular emphasis to any passage of the composition being re corded, the operator will, by moving the shutter 34, uncover to the necessary extent the opening 31, or when a passage is to be subdued in power or loudness the shutter is moved into a position which leaves a smaller portion of the opening uncovered. This movement of the shutter back and forth to intercept more or less of the light rays emanating from the lamp 32 is continued throughout the entire recording process with the result that a dynamic record 35 is obtained upon the film.

Referring now to Figure 3, which illustrates diagrammatically an arrangement for reproducing the sound records 22 and 23 and for imparting thereto the shading in tones which the composition originally called for, it will be seen that in addition to the light sources 25 for influencing the photo-electric cells 24, there is employed an auxiliary light source 36 by means of which a corresponding photo-electric cell 37 is influenced by the dynamic record 35 passing said light source 36. Thelight variations produced as the record 35 passes its light source influence the cell 37 and the latter in turn converts these light variations into corresponding electrical variations for operating a solenoid 38. Con nected to the armature 39 of the solenoid is a rheostat arm 40 which is arranged to cut-in or cut-out portions of the resistance 41 de pending upon the extent of energization of the solenoid.

As appears clearly in Figure 1, the variable resistance 41is connected in parallel with the resistances 30 of the circuits 27 and 28. Suitable switches 42 and 43' are employed for respectively connecting the resistance 41 in series in each of the circuits 27 and 28 simultaneously as the resistances 30 are disconnected therefrom, this being the proccdure when sound shading is desired. WVhen, however, the dynamic record is not to be used the switch 42 is opened and the more or less light from the lamp 36 depending upon the degreesofeshading in the dynamic record 35. Wherea passage requires that the music be played withforce and'em phasis, the portion of the dynamic record 35 corresponding to this passage will permit a greater intensity of light from the lamp 36 to influence the cell 37 with the result that the solenoid 38 will be energized to a corresponding degree. ature 39 will actuate the rheostat arm 40 in such manner as to decrease the resistance 41 and thereby permit a greater flow o'f current in each of the circuits 27 and 28. Conversely, where less emphasis is desired in any particular passage the d namic record will cause the photo-electric ce 1 37 to be less influenced by the light from the lamp 36 with the final result that the resistance 41 will be increased and thereby decrease the flow of current in the circuits 27 and 28. It follows that any degree of shading may be 'vento the reproduced tones and that the c aracter'and expressive emphasis of the reproduced composition as a whole is governed entirely by the dynamic record 35 without the attention of an operator.

It will be understood, of course, that various changes may be made from time to time in the invention described herein without departing from the spirit or principles thereofand accordingly it is intended to claim the same broadly as well as specifically as indicated in the appended claims.

What is claimed as new and useful is:

1. In an apparatus for photographically recording sounds, in combination, means for converting sound waves into corresponding electrical variations, means for recording said electrical variations upon a photographic film, and means operable manually to photographically produce simultaneously as said sound waves are recorded upon the film, an auxiliary sound shading record upon the same film or upon another film operable in synchronism with the sound record film.

2. In an apparatus .for photographically recording sounds, in combination, means for converting the sounds into corresponding electrical variations, means for recording said electrical variations upon a photographic film, and manually operated means operable independently of said first mentioned means to photographically produce upon a photographic film, simultaneously as said sound waves are recorded an auxiliary sound shad ing record which is in accord with thedynamic shading of the sounds as originally produced;

3. In an apparatus for photographically recording sounds, in combination, means for photographically recording upon a film the Consequently, the solenoid armupon the photographic film,

I ing upon constant intensity,

sounds as originally produced, and means 0perable manually to photographically produce simultaneously as said sounds are recorded thereon, a record of the dynamic shading of the sounds as originally produced.

4:. In an apparatus for photographically producing sounds, in combination, a microphone circuit including a lamp the intensity of which varies in accordance with the sound variations whereby to produce upon the film a record of the sound variations, means for photographically influencing the film independently of said sound recording lamp to produce a sound shading record thereon, and means operable manually for varying the intensity to which the film is influenced by said last mentioned means.

5. In an apparatus for photographically recording sounds, in combination, manually operated means for photographically producthe sound record film or upon a separate film operating in synchronism therewith a sound shading or dynamic record corresponding to the variations in power or loudness of the sounds as originally produced, said latter record being entirely independent of the sound record.

6. In an apparatus'for photographically recording sounds, in combination, a light source, means influenced by the sound variations to vary the intensity of said light source whereby to photographically produce a record of said sound variations, a second and constant source of light, and manually operated means for intercepting to a greater or less extent the light rays emanating from said second source of light whereby to produce a photographic record corresponding to the variations in power or loudness of the sounds as originally produced.

7 In an apparatus for photographically recording sounds, in combination, a plural ty of light sources arranged to independently 1nfluence separate portions of a photographic film or films, one of said light sources being operatively associated with a sound responsive device for producing light rays which vary in intensity in accordance with the va-' riations of the sounds as originally produced and another of said light sources being operable to produce light rays of substantially and manually operated means for intercepting to greater or less extent the light rays of constant intensity to produce upon the film a sound shading or dynamic record corresponding to the variations in power or loudness of said originally produced sounds.

8. The method for producing a sound shading record upon a photographic film having a sound record thereon, said sound shading record being incapable of reproducing the recorded sounds which consists in subjecting a separate portion. of the film to a constant source of light and then manually varying the degree to which said portion of the film is subjected to said light by exposing more or less of the film in accordance with the variations in power or loudness of the sounds as originally produced.

9. The method for photographically producing a sound shading record, the latter being separate and distinct from the sound record itself, which consists in subjecting the film to a constant source of light and then manually varying the extent to which said film is subjected to said light by exposing more or less of the film to said light accordingly as the sounds are increased or diminished in power or loudness.

10. The method of photographically producing a dynamic record as distinguished from a sound record upon a film which consists in causing a certain portion of the film to traverse the light rays emanating from a constant source of light and in manually increasing or decreasing the exposed width of said portion of the film whereby to produce areas of exposure varying accordingly as the sounds are increased or diminished in power or loudness.

11. In an apparatus for photographically reproducing sounds, in combination, means for producing a photographic sound record, manually controlled means for photogrpahically producing a sound shading record simultaneously as said sound record is produced, said records being synchronously operable to independently influence separate photo-electric cell circuits whereby to establish current variations in said circuits, means incorporated in that one of said circuits which is influenced by the sound record for reproducing the sounds recorded thereon, and means incorporated in the other of said circuits for automatically increasing or decreasing the power or loudness of the reproduced sounds in accordance with the current variations produced by said sound shading record.

12. In an apparatus for reproducing sounds, in combination, means for concurrently producing upon a film photographically recorded sound and sound shading records, said records being independent of each other and the latter being incapable of reproducing sounds in accordance with those as originally produced, a plurality of independent light sources arranged to one side of the film, a plurality of light responsive devices arranged to the opposite side of said film selectively responsive to the light rays emanating from said sources of light, each of said light responsive devices being included in a separate electrical circuit, means for individually passing said sound and sound shading records between said light sources and their respective light responsive devices whereby to set up in the several circuits electrical variations corresponding in intensity to the light variations influencing the several light responsive devices, and means operable in accordance with the current variations set up by the sound shading record to vary the current variations set up by the sound record.

13. In an apparatus for reproducing sounds, in combination, means for producing a photographically recorded sound record, means for converting the recorded sound 10 variations into corresponding electrical variations, meansoperable concurrently with said first-mentioned means for producing a photographically recorded sound shading record obtained independently of the recorded sounds, and means influenced by said sound shading record to change the value of the current variations established by said sound record. 7 p i 1-4. In an apparatus for photographically reproducing sounds, in combination, means for concurrently producing a photographically recorded sound record and an independent photographically recorded sound shading record, means respectively influenced by said records for establishing separate circuits of varying current, means incorporated in the sound record circuit for reproducing the sounds recorded photographically, and means incorporated in the sound shading 3 record circuit and operable to automatically vary the resistance of the other circuit whereby to produce sounds which vary in power or loudness.

15. The method of producing a sound shading record for governing the dynamic shading of reproduced sounds which consists in manually exposing more or less of a photographic film to a constant source of light simultaneously as the sounds to be reproduced are being recorded whereby to produce varying areas of exposed film surface, said varying areas being in correspondence with the variations in power or loudness of the sounds as originally produced. In testimony whereof, I have hereunto affixed my signature.

BERNARD KWARTIN. 

